The LDINTR register caries both interrupt enable and interrupt status
bits. When setting or clearing interrupt enable bits, write all status
bits to 1 to avoid acknowledging interrupts by mistake.
When acknowledging interrupts, write 1 to all non-triggered interrupt
bits to avoid losing interrupts.
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
drivers/video/sh_mobile_lcdcfb.c | 20 ++++++++------------
1 files changed, 8 insertions(+), 12 deletions(-)
diff --git a/drivers/video/sh_mobile_lcdcfb.c b/drivers/video/sh_mobile_lcdcfb.c
index 7d77651..32f884e 100644
--- a/drivers/video/sh_mobile_lcdcfb.c
+++ b/drivers/video/sh_mobile_lcdcfb.c
@@ -318,19 +318,13 @@ static irqreturn_t sh_mobile_lcdc_irq(int irq, void *data)
{
struct sh_mobile_lcdc_priv *priv = data;
struct sh_mobile_lcdc_chan *ch;
- unsigned long tmp;
unsigned long ldintr;
int is_sub;
int k;
- /* acknowledge interrupt */
- ldintr = tmp = lcdc_read(priv, _LDINTR);
- /*
- * disable further VSYNC End IRQs, preserve all other enabled IRQs,
- * write 0 to bits 0-6 to ack all triggered IRQs.
- */
- tmp &= ~LDINTR_STATUS_MASK & ~LDINTR_VEE;
- lcdc_write(priv, _LDINTR, tmp);
+ /* Acknowledge interrupts and disable further VSYNC End IRQs. */
+ ldintr = lcdc_read(priv, _LDINTR);
+ lcdc_write(priv, _LDINTR, (ldintr ^ LDINTR_STATUS_MASK) & ~LDINTR_VEE);
/* figure out if this interrupt is for main or sub lcd */
is_sub = (lcdc_read(priv, _LDSR) & LDSR_MSS) ? 1 : 0;
@@ -342,7 +336,7 @@ static irqreturn_t sh_mobile_lcdc_irq(int irq, void *data)
if (!ch->enabled)
continue;
- /* Frame Start */
+ /* Frame End */
if (ldintr & LDINTR_FS) {
if (is_sub == lcdc_chan_is_sublcd(ch)) {
ch->frame_end = 1;
@@ -971,9 +965,11 @@ static int sh_mobile_wait_for_vsync(struct fb_info *info)
unsigned long ldintr;
int ret;
- /* Enable VSync End interrupt */
+ /* Enable VSync End interrupt and be careful not to acknowledge any
+ * pending interrupt.
+ */
ldintr = lcdc_read(ch->lcdc, _LDINTR);
- ldintr |= LDINTR_VEE;
+ ldintr |= LDINTR_VEE | LDINTR_STATUS_MASK;
lcdc_write(ch->lcdc, _LDINTR, ldintr);
ret = wait_for_completion_interruptible_timeout(&ch->vsync_completion,
--
1.7.3.4
--
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